Microphone structure sealed by MEMS capacitance pressure chip

Abstract

The utility model discloses a microphone structure sealed by an MEMS capacitance pressure chip, comprising a PCB provided with a first through hole; the back cavity of the MEMS pressure sensor chip is aligned with the first through hole; the ASIC chip is connected with the MEMS pressure sensor chip through a lead; the first shell covers the ASIC chip and the MEMS pressure sensor chip, a first vent hole is formed in the first shell, and the first vent hole and the first through hole are arranged in a staggered mode; the second shell covers the first shell, and a second vent hole is formed in the second shell; and the oil-proof breathable film seals the second vent hole. Compared with the prior art, the microphone structure provided by the utility model solves the problems of high packaging cost and low yield caused by a secondary packaging process of the microphone structure.

Description

Technical Field

[0001] The utility model relates to the technical field of micro-electromechanical packaging, in particular to a microphone structure of a MEMS capacitor pressure chip seal. Background Art

[0002] The MEMS capacitor pressure chip is an important device for controlling the operation of the electronic atomizer. The MEMS capacitor pressure chip consists of an electrode plate and a diaphragm with a gap between them. When the user takes a puff, the suction side of the diaphragm is in a negative pressure state, forming a pressure difference with the other side of the diaphragm. The change in air pressure will cause the diaphragm to deform, causing the capacitance value between the electrode plate and the diaphragm to change, which is converted into an electrical signal output to control the atomizer to atomize.

[0003] In electronic atomizers, it is usually necessary to encapsulate the MEMS capacitor pressure chip, ASIC chip, and other capacitor and resistor devices in a specific structure to realize the signal conversion control function and isolate and protect the MEMS chip from external influences.

[0004] There are usually two types of electronic atomizer microphone structures that use MEMS capacitive pressure chips:

[0005] 1) First package the MEMS chip and ASIC chip, place them on the same PCB board, buckle the metal shell, then seal the sensor module and other components such as capacitors, resistors, and LEDs on the atomizer microphone PCB board, and buckle the metal shell again;

[0006] 2) The MEMS capacitor pressure chip and the plastic-sealed ASIC chip and other electronic components that have been packaged are sealed together on the atomizer microphone PCB board and covered with a metal shell.

[0007] Both of the above technical solutions require two packaging processes: first, the MEMS chip and ASIC chip are packaged once, and then the electronic atomizer microphone is packaged twice. The process is complicated, the cost is increased, and it will have an adverse effect on the MEMS chip itself. Specifically, the disadvantages of two packaging include the following three points:

[0008] 1. The capacitor pressure chip undergoes two high-temperature eutectic welding processes. The stress mismatch caused by high temperature will cause the sensitivity of the capacitor pressure chip to change or even fail. The static electricity during the eutectic welding process will also cause the diaphragm of the capacitor pressure chip to be attracted, making the chip unable to work normally.

[0009] Second, the two-step lamination process will increase the chance of microphone leakage, resulting in reduced sensitivity or even failure of the microphone;

[0010] 3. Two-time packaging increases costs and process difficulty and reduces packaging efficiency. Utility Model Content

[0011] The utility model aims to provide a microphone structure for sealing a MEMS capacitor pressure chip, so as to solve the problems of high packaging cost and low yield rate caused by the secondary packaging process of the microphone structure.

[0012] In order to achieve the above-mentioned purpose, the utility model provides a MEMS capacitive pressure chip sealed microphone head structure, comprising:

[0013] A PCB board having a first through hole disposed thereon;

[0014] A MEMS pressure sensor chip is fixedly mounted on the PCB, and the back cavity of the MEMS pressure sensor chip is aligned with the first through hole;

[0015] An ASIC chip is arranged on one side of the MEMS pressure sensor chip, and the ASIC chip is connected to the MEMS pressure sensor chip through leads;

[0016] A first housing is fixedly mounted on the PCB board, the first housing covers the ASIC chip and the MEMS pressure sensor chip, and a first vent hole is provided on the first housing, and the first vent hole and the first through hole are staggered;

[0017] Components, which are fixedly mounted on the PCB;

[0018] A second shell body, which covers and includes the first shell body, and a second vent hole is provided on the second shell body;

[0019] The oil-proof and breathable membrane is arranged on the surface of the second shell body, and the oil-proof and breathable membrane closes the second vent hole.

[0020] As a further description of the above technical solution:

[0021] The MEMS pressure sensor chip is bonded to the PCB board.

[0022] As a further description of the above technical solution:

[0023] The diameter of the second ventilation hole is greater than the diameter of the first ventilation hole.

[0024] As a further description of the above technical solution:

[0025] The oil-proof and breathable membrane is bonded to the surface of the second shell.

[0026] As a further description of the above technical solution:

[0027] A soldering pad is provided on the back of the PCB board.

[0028] A MEMS capacitive pressure chip sealed microphone structure, the packaging process includes the following steps:

[0029] S1. Pad production: prepare the PCB board and lead out several pads on the back of the PCB board;

[0030] S2, punching: punching a hole on the PCB board to form a first through hole;

[0031] S3, MEMS pressure sensor chip arrangement: fix the MEMS pressure sensor chip at the first through hole position on the front side of the PCB board so that the back cavity of the MEMS pressure sensor chip is aligned with the first through hole;

[0032] S4. ASIC chip layout: The ASIC chip is fixedly mounted on the PCB board, the ASIC chip is arranged on one side of the MEMS pressure sensor chip, and the ASIC chip is connected to the MEMS pressure sensor chip through leads;

[0033] S5. Installing the first housing: fixing the first housing on the PCB, the first housing covering the ASIC chip and the MEMS pressure sensor chip, and providing a first vent hole on the first housing, wherein the first vent hole and the first through hole are staggered;

[0034] S6. Fixing components: attaching components to the outer area of ​​the first housing on the front side of the PCB board according to the preset modulation circuit position;

[0035] S7, installing the second housing: fixing the second housing on the PCB, the second housing covering the first housing, and the second housing being provided with a second vent hole;

[0036] S8, finished product: an oil-proof breathable film is attached to the surface of the second shell, and the oil-proof breathable film closes the second vent hole.

[0037] In summary, due to the adoption of the above technical solution, the beneficial effects of the utility model are:

[0038] 1. In the utility model, the high-temperature welding process in the packaging process is reduced, thereby reducing the adverse effects of the capacitor pressure chip sensitivity change and electrostatic attraction caused by high-temperature welding, and improving the packaging yield.

[0039] 2. In the utility model, a one-time packaging technology is adopted to reduce the number of bonding times, and there is no need for secondary patch packaging, which reduces the probability of air leakage at the patch sealing port and the probability of air leakage at the microphone head, while reducing the process difficulty, reducing costs and improving yield.

[0040] 3. In the present invention, only one PCB board is needed, which can reduce the number of PCB boards by one, thereby reducing the cost in production, simplifying the packaging process in terms of process flow, and improving production efficiency.

[0041] 4. In the utility model, stress changes of the sensitive film of the air pressure chip caused by multiple patch packaging processes, electrostatic adsorption and other undesirable phenomena are reduced, the stability and accuracy of the MEMS capacitor pressure chip are ensured, and the packaging yield is improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0042] In order to more clearly illustrate the technical solutions of the embodiments of the utility model, the drawings required for use in the embodiments will be briefly introduced below. It should be understood that the following drawings only show certain embodiments of the utility model and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other relevant drawings can be obtained based on these drawings without paying creative work.

[0043] Figure 1 It is a structural schematic diagram of a microphone structure sealed with a MEMS capacitor pressure chip.

[0044] Figure 2 This is a schematic diagram of the structure of a microphone head sealed with a MEMS capacitor pressure chip from an upward angle.

[0045] Figure 3 This is a construction diagram of step S1 in the packaging process of a microphone structure for sealing a MEMS capacitor pressure chip.

[0046] Figure 4 This is a construction schematic diagram of step S3 in a packaging process of a microphone structure for sealing a MEMS capacitor pressure chip.

[0047] Figure 5 This is a construction schematic diagram of step S4 in a packaging process of a microphone structure for sealing a MEMS capacitor pressure chip.

[0048] Figure 6 This is a construction schematic diagram of step S5 in a packaging process of a microphone structure for sealing a MEMS capacitor pressure chip.

[0049] Figure 7 This is a construction schematic diagram of step S6 in a packaging process of a microphone structure for sealing a MEMS capacitor pressure chip.

[0050] Figure 8 This is a construction diagram of step S7 in a packaging process of a microphone structure for sealing a MEMS capacitor pressure chip.

[0051] Legend:

[0052] 1. PCB board; 11. solder pad; 12. first through hole; 2. MEMS pressure sensor chip; 3. ASIC chip; 31. lead; 4. first shell; 41. first vent hole; 5. components; 6. second shell; 61. second vent hole; 7. oil-proof breathable membrane. DETAILED DESCRIPTION

[0053] In order to make the purpose, technical scheme and advantages of the embodiments of the utility model clearer, the technical scheme in the embodiments of the utility model will be clearly and completely described below in conjunction with the drawings in the embodiments of the utility model. Obviously, the described embodiments are part of the embodiments of the utility model, not all of the embodiments. Generally, the components of the embodiments of the utility model described and shown in the drawings here can be arranged and designed in various different configurations.

[0054] Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the present invention to be protected, but merely represents selected embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0055] It should be noted that similar reference numerals and letters denote similar items in the following drawings, and therefore, once an item is defined in one drawing, further definition and explanation thereof is not required in subsequent drawings.

[0056] In the description of the embodiments of the present utility model, it should be noted that the terms "upper", "inner", etc. indicate directions or positional relationships based on the directions or positional relationships shown in the accompanying drawings, or are directions or positional relationships in which the utility model product is usually placed when in use. They are only for the convenience of describing the present utility model and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific direction, be constructed and operated in a specific direction, and therefore cannot be understood as a limitation on the present utility model.

[0057] In the description of the present invention, it is also necessary to explain that, unless otherwise clearly specified and limited, the terms "set", "install", "connect", and "connect" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a direct connection, or an indirect connection through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0058] Example 1

[0059] See also Figure 1-8 The utility model provides a MEMS capacitive pressure chip sealed microphone structure, including:

[0060] A PCB board 1 is provided with a first through hole 12, and the first through hole 12 is connected to the external environment;

[0061] The MEMS pressure sensor chip 2 is fixedly mounted on the PCB board 1, and the back cavity of the MEMS pressure sensor chip 2 is aligned with the first through hole 12;

[0062] An ASIC chip 3, which is disposed on one side of the MEMS pressure sensor chip 2, and the ASIC chip 3 is connected to the MEMS pressure sensor chip 2 via a lead 31;

[0063] A first housing 4 is fixedly mounted on the PCB board 1. The first housing 4 covers the ASIC chip 3 and the MEMS pressure sensor chip 2. A first vent hole 41 is provided on the first housing 4. The first vent hole 41 and the first through hole 12 are staggered.

[0064] Components 5, which are fixedly mounted on the PCB board 1;

[0065] A second shell 6, which covers the first shell 4, and a second vent hole 61 is provided on the second shell 6;

[0066] The oil-proof and breathable membrane 7 is disposed on the surface of the second shell 6 , and the oil-proof and breathable membrane 7 closes the second vent hole 61 .

[0067] The MEMS pressure sensor chip 2 is bonded to the PCB board 1. Specifically, the MEMS pressure sensor chip 2 is fixed to the PCB board 1 by adhesive bonding, without high temperature welding, thereby improving the packaging yield.

[0068] The diameter of the second vent hole 61 is greater than the diameter of the first vent hole 41 , thereby improving the sensitivity of the microphone.

[0069] The oil-proof and breathable membrane 7 is bonded to the surface of the second shell 6, and high-temperature welding is not required, thereby improving the packaging yield.

[0070] A soldering pad 11 is disposed on the back side of the PCB board 1 .

[0071] A MEMS capacitive pressure chip sealed microphone structure, the packaging process includes the following steps:

[0072] S1, pad production: prepare PCB board 1, plan circuit routing on PCB board 1, and lead out five pads 11 on the back side of PCB board 1;

[0073] S2, punching: punching a hole on the PCB board 1 to form a first through hole 12;

[0074] S3, MEMS pressure sensor chip arrangement: fix the MEMS pressure sensor chip 2 at the first through hole 12 on the front side of the PCB board 1, so that the back cavity of the MEMS pressure sensor chip 2 is aligned with the first through hole 12;

[0075] S4, ASIC chip arrangement: The ASIC chip 3 is fixed on the PCB board 1 by eutectic welding or silver paste bonding, and the ASIC chip 3 is arranged on one side of the MEMS pressure sensor chip 2. The ASIC chip 3 is connected to the MEMS pressure sensor chip 2 by a lead 31;

[0076] S5. Installing the first housing: The first housing 4 is fixedly installed on the PCB board 1. The first housing 4 covers the ASIC chip 3 and the MEMS pressure sensor chip 2. The first housing 4 is provided with a first vent hole 41. The first vent hole 41 and the first through hole 12 are staggered.

[0077] S6, component fixing: attaching components 5 to the outer area of ​​the first housing 4 on the front side of the PCB board 1 according to the preset modulation circuit position, the components 5 including modulation resistors and capacitors;

[0078] S7, installing the second housing: fixing the second housing 6 on the PCB board 1, the second housing 6 covers the first housing 4 and all other electronic components on the PCB board 1, and the second housing 6 is provided with a second vent hole 61;

[0079] S8, finished product: the oil-proof and breathable membrane 7 is attached to the surface of the second shell 6, and the oil-proof and breathable membrane 7 closes the second vent hole 61.

[0080] Working principle: The MEMS pressure sensor chip 2 is connected to the ASIC chip 3 by means of leads, and the first shell 4 with a vent is used to cover the MEMS pressure sensor chip 2 and the ASIC chip 3 together. The vent provided in the first shell 4 is offset from the first through hole 12 on the PCB board 1 and is not perpendicular to each other. The modulation capacitor and resistor are bonded to the PCB board 1 around the first shell 4, and then the entire assembly including the first shell 4 is covered with a second shell 6 with a vent. The pad 11 provided on the back of the PCB board is used to make an electrical connection with the outside. When the user performs the inhalation action, the gas passes through the first through hole 12 on the PCB board 1 to deform the diaphragm of the MEMS pressure sensor chip 2, thereby causing a change in capacitance. The capacitance change signal is processed by the ASIC chip 3, and a drive signal is output to make the electronic atomizer work.

[0081] The above description is only a preferred specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Any technician familiar with the technical field can make equivalent replacements or changes within the technical scope disclosed by the present invention according to the technical scheme and the utility model concept of the present invention, which should be covered by the protection scope of the present invention.

Claims

1. A MEMS capacitive pressure chip sealed microphone structure, characterized in that: include: A PCB board having a first through hole disposed thereon; A MEMS pressure sensor chip is fixedly mounted on the PCB board, and the back cavity of the MEMS pressure sensor chip is aligned with the first through hole; An ASIC chip, which is arranged on one side of the MEMS pressure sensor chip, and the ASIC chip is connected to the MEMS pressure sensor chip through leads; A first shell, which is fixedly mounted on the PCB board, the first shell covers and contains the ASIC chip and the MEMS pressure sensor chip, the first shell is provided with a first vent hole, and the first vent hole and the first through hole are staggered; Components, which are fixedly mounted on the PCB; A second shell, which covers and includes the first shell, and the second shell is provided with a second vent hole; An oil-proof and breathable membrane is arranged on the surface of the second shell, and the oil-proof and breathable membrane closes the second vent hole.

2. According to claim 1, a MEMS capacitive pressure chip sealed microphone structure is characterized in that: The MEMS pressure sensor chip is bonded to the PCB board.

3. The MEMS capacitive pressure chip sealed microphone structure according to claim 1, characterized in that: The diameter of the second ventilation hole is greater than the diameter of the first ventilation hole.

4. The MEMS capacitive pressure chip sealed microphone structure according to claim 1, characterized in that: The oil-proof and breathable membrane is bonded to the surface of the second shell.

5. The MEMS capacitive pressure chip sealed microphone structure according to claim 1, characterized in that: A soldering pad is arranged on the back side of the PCB board.

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